Method of making oil seals

ABSTRACT

A fluid seal having an annular metal case supporting a flexible sealing ring with a peripheral sealing edge radially to one side of an axial web of the case. The other side of the web may be formed with a groove filled with the resilient material of the sealing ring. A radial web of the case is also provided at one edge of the axial web. The metal case is made by a roll forming process.

United States Patent Potter 51 Aug. 22, 1972 METHOD OF MAKING OIL SEALSCharles William Potter, Manchester, England Inventor:

Assignee: Charles Weston and Company Limited, Lancashire, England Filed:Dec. 9, 1969 App1.No.: 883,656

Foreign Application Priority Data Dec. 10, 1968 Great Britain..58,517/68 US. Cl ..29/400, 29/148.4 S, 29/D1G. 34,

g 277/ 153 Int. Cl. ..B23p 17/00, F16j 15/32 Field ofSearch.....277/l38, 153; 29/521, 400 D,

29/D1G. 34, 148.4 S; 72/168, 166

References Cited UNITED STATES PATENTS Chandler ..29/D1G. 34

2,934,989 5/ 1960 Belli et al ..29/D1G. 34 2,982,999 5/1961 Stewart..29/D1G. 34 3,090,996 5/ 1963 Reichenbach et a1 ..29/

D16. 34 1,043,832 11/1912 Herr ..29/400 D Primary Examiner-Robert 1.Smith Attorney-Holman & Stern 57 ABSTRACT A fluid seal having an annularmetal case supporting a flexible sealing ring with a peripheral sealingedge radially to one side of an axial web of the case. The other side ofthe web may be formed with a groove filled with the resilient materialof the sealing ring. A radial web of the case is also provided at oneedge of the axial web. The metal case is made by a roll form ingprocess.

3 Clains, 3 Drawing Figures METHOD OF MAKING OIL SEALS BACKGROUND OF THEINVENTION This invention relates to the production of fluid seals whichare rings used to seal annular spaces between housings and rotary orreciprocating shafts, bearings and the like to prevent leakage of fluidfrom and ingress of foreign matter to said housings.

It is well known for such seals to compromise a flexible ring of rubberor like resilient material providing a peripheral sealing edge, and arigid metal case of annular shape to which the rubber ring is secured bymolding therewith. Conventionally, the metal case consists of an axialweb and a radial flange giving the case a generally L-shapedcross-sectional appearance. The peripheral sealing edge of the rubberring may be radially within the axial web of the metal case which isthen a tight fit in the housing, or it may be radially outside such webif the case is to fit onto the shaft, bearing or the like. It isadvantageous to the performance of the oil seal if the material of theflexible ring lies to both sides of the axial web of the metal case soas to avoid a purely metal-to-metal connection between the housing andthe case or between the case and the shaft, bearing or the like. Thishas been accomplished by suspending the metal case in a die in which theflexible ring is molded with an axial web in which the axial metal webbecomes embedded during the molding operation. It is necessary with thismolding method to ensure that the metal case is accurately located inthe die and does not become displaced therein during molding.

The metal case of previously proposed fluid seals has been produced bythe method of press raising and piercing from sheet metal materialeither in a single operation using combination tools or in separateoperations for the raising of the axial web and subsequent piercing todefine the radial flange. This method of production has a considerabledisadvantage in that it leads to wastage of material. Also, it isdifficult to modify the cross-sectional shape of the case to" increaserigidity.

An object of the present invention is to obviate or mitigate the abovedescribed disadvantages and difficulties.

SUMMARY OF THE INVENTION According to a first aspect of the presentinvention, there is provided in a method of manufacturing a fluid sealincluding a flexible ring of rubber or like resilient material securedto a metal case, the step of making the metal case by roll forming anarrow metal strip into a complete or nearly complete ring of metal ofthe required cross-section.

According to a second aspect of the present invention, there is provideda fluid seal manufactured in accordance with the method defined in theimmediately preceding paragraph. I

According to a third aspect of the present invention, there is providedan oil seal comprising a flexible ring of rubber or like resilientmaterial having a peripheral sealing edge, a metal case manufactured inaccordance with the method of said first aspect of the inventioncoaxially and concentrically disposed relative and connected to saidflexible ring and comprising an axial web provided at one edge with aradial flange, said axial web being formed with a peripheral groove onone side and BRIEF DESCRIPTION OF THE INVENTION FIG. 1 is a cut-awaysectional perspective view of a first embodiment of fluid seal inaccordance with the invention;

FIG. 2 is a like view of a second embodiment of the fluid seal, and vFIG. 3 is a similar view of a third embodiment of the fluid seal.

DETAILED DESCRIPTION OF THE DRAWING DETAILED DESCRIPTIONOF THE DRAWING eAs shown in FIG. 1, a first embodiment of an oil seal in accordance withthe invention comprises an annular metal case denoted generally 1consisting of an axial web 1a formed at an edge thereof with a flange lbdisposed at right angles to and radially inwards of said web la andconnected to a flexible ring 2 of rubber or like resilient material. Theflexible ring 2 is substantially U or V-shaped in profile having a firstaxial web 2a applied to the inner surface of the metal case 1 and asecond axial web 2b also extending radially inwards of the metal case 1,connected to said first web 2b adjacent the radial flange 1b of themetal case 1. A lip 20 at the free edge of the second web 2b providesthe sealing edge of the oil seal with the shaft bearing or the like towhich it is fitted, and a circular coil or garter spring 3 between thetwo webs 2a, 2b of the flexible ring 2 serves to hold the sealing edge20 against the surface to be sealed.

Adjacent the radial flange lb, the axial web la of the metal case 1 isformed on its radially inner surface with a circumferential rib 1c ofarcuate cross-section which defines a peripheral groove 1d on the outersurface of the metal case 1. Flat portions 1e, 1f of the case axial web1a on opposite sides of the peripheral groove 1d are of differentdiameters with that portion 1f of the web which is adjacent the annularflange 1b being of the smaller diameter. This smaller diameter portionIf and the adjacent groove 1d are both covered by the resilient materialof the flexible ring 2 to form a resilient surface which projectsslightly outwards beyond the plane containing the adjoining metalsurface of the larger diameter portion 1e of the axial web la.

The oil seal described above is made as follows. A strip of metal isroll formed into a circular ring of the required cross-section to formthe metal case 1 which is described above. The case is then located in adie to mold the fleible ring, and because the outer axial surface of thecase is not to be wholly covered by the resilient material of theflexible ring, the case can be positively located in the die withoutrisk of displacement during the molding operation.

the outer sealing to be stripped or damaged through pressing into thehousing is resisted due to the fact that the resilient material has alarge area bonded to the case 1 in the groove 1d and only a relativelysmall area exposed beyond the groove. The outer diameter sealer, as theresilient material on the outside of the case 1 is called, is preferablyabout one-third of the axial length of the metal case 1 and compensatesfor any small variations in the radial dimensions of the metal case.

When oil seals are fitted into housings made of different materials tothe metal of the case, problem have previously arisen because of thedifierent coefficients of expansion of the housing and case materials.Also, the housing had to be bored to a close tolerance which wasuneconomical. Both these disadvantages are obviated by having an axialsplit 4 between the ends of the roll formed annular strip of the metalcase and filling this split with resilient material to provide for avariable degree of interference between the housing and the metal case.

In a second embodiment of fluid seal in accordance with the invention,the flexible sealing ring 2 is pro vided radially outside the metal case11 (as shown in F IG. 2) so as to seal against the housing and fit thecase 1 l immovably on the rotary or reciprocating shaft, bearing or thelike. In this event, the ends of the roll formed strips of the metalcase 11 are welded together to form a continuous metal ring with theradial flange 11b of the case directed outwardly. In this instance, thearrangement and dispositions of the flexible sealing ring 12 arereversed relative to the metal case 1 1 to that described above, and theradial flange 11b of the metal case 11 extends outwardly of the axialweb lla as does the circumferential rib formation 1 10.

By providing a narrower radial flange lb, 11b than conventional fluidseals, the radial dimensions from the sealing edge 20, of the flexiblering 2, 12 to the free edge .of the flange lb, 11b can be increasedrelative to conventional fluid seals of the same size thus making thefluid seals more flexible. A sufficient degree of flexibility can bemaintained even if the radial dimensions are decreased from thatillustrated and his therefore possible to use this fluid seal to seal anarrower annular gap than was envisaged with conventional fluid seals.

It will be appreciated that, apart from those described above, numerousother modifications and variations are possible without departingmaterially from the scope of the invention. For example, in a thirdembodiment of fluid seal as illustrated in FIG. 3, the flexible ring 22is formed with an extension on its sealing web so that it is providedwith two axially spaced sealing lips 22c and 22d. In other respects thethird embodiment is identical with the first embodiment illustrated inFIG. 1.

It is obvious that the method of manufacturing metal cases by rollforming is applicable to the manufacture of cases for conventional fluidseals, but one of its major advantages is that it lends itself to themanufacture of cases having novel features which make possible theproduction of new and improved oil seals.

What iscai e is: l. A met 03 0? manufacturing a fluid seal having ametal case and a ring of resilient material secured to the case,including the steps of roll forming a strip of metal to provide anannular metal case for the seal, positively locating the annular metalcase in a die, and molding a resilient like material to a portion of oneof the inner and outer circumferential surfaces of the metal case.

2. The method of manufacturing a fluid seal as claimed in claim 1,including welding the ends of the rolled metal strip together toconstitute a continuous metal ring.

3. The method of manufacturing a fluid seal as claimed in claim1,.comprising providing an axial split in the metal case, and fillingthe axial split with a resilient material.

1. A method of manufacturing a fluid seal having a metal case and a ring of resilient material secured to the case, including the steps of roll forming a strip of metal to provide an annular metal case for the seal, positively locating the annular metal case in a die, and molding a resilient like material to a portion of one of the inner and outer circumferential surfaces of the metal case.
 2. The method of manufacturing a fluid seal as claimed in claim 1, including welding the ends of the rolled metal strip together to constitute a continuous metal ring.
 3. The method of manufacturing a fluid seal as claimed in claim 1, comprising providing an axial split in the metal case, and filling the axial split with a resilient material. 